I never ran 80 +. My best was 78.1 @ 3.5lbs boost. I can offer my experience though. My boat would get very loose starting around 72mph like clock work. Sometimes I could drive through it and sometimes I couldn't and would have to trim the drive down, get out of the throttle or drop some tab to clean it up.
The more seat time I got the more often I could drive though it as I was able to anticipate the reaction of the boat. I do think that part of my problem stemmed from the steering system. I did have dual ram external steering but it was only a half system so it still had a cable going to the helm that had some slop in it.
I experienced the looseness when I was in flat water and a lot of trim. However, I have run the boat in the Chesapeake Bay with about 1' chop and the tabs a little below neutral and run 75 GPS and not got loose. But the attitude of the boat was different since it wasn't trimmed to the hilt.
I was originally gonna say that 80mph is very fast for this hull but I am not so sure that is an accurate or fair statement. I think 80mph is very fast when you are trimmed to the hilt and the only thing in the water is the pad. If you can run 80+ while not having to trim up so much or trim to optimum RPM but drag a little tab then she'll be stable and a blast to drive.
One last thing, there is more to consider than top speed. My boat was overall way more fun with the blower than without. The acceleration and mid-range cruise was much nicer. I don't regret putting a supercharger on my 288.
Splinter explained it perfectly!!! after some seat time, I also have fun driving her. I'm a little faster though best so far is just under 83 MPH 2 people 1/2 tank gas. I'm running 6 lbs of boost. This weekend on Lake Champlain, I had a boat load of guys (7 including myself) 1/2 tank again, and hit 75 mph. It rode like it was on rails with all those fat @$$es on the boat.
My prop is stock, and plan on working her over the winter. I think she'll do 85 with a little prop work, my slip factor is a little high, and I have plenty of RPM's to work with...
Thanks guys. What are you turnning? Bravo ones, Mirages? How has your drives held up? Are they just the regular Bravo? Are you guys worried about the drive? How was your fuel consumtion compared to before at say 65 mph or a nice cruise speed?
I know Claude has a Stock Bravo One 4 blades I think 28" from running on Champlain with him this weekend. Running?? more like sitting talking boats and all that nice stuff!
My best friend and fellow Sunsation owner has a 2000 288 that has ran a best of 91.5 a few years back at the Richmond Radar Run. This is with a 540 and 1071 blower. He was turning a labbed 30" Bravo at 5500 RPMs.
I think Kanookster is right with seat time being the issue. It takes very small corrections to the steering wheel (usually to the left, against prop rotation) to keep the boat up on the pad. I also think it helps to have plenty of HP to keep the boat "pulling" through any chine walk.
Thanks guys. What are you turnning? Bravo ones, Mirages? How has your drives held up? Are they just the regular Bravo? Are you guys worried about the drive? How was your fuel consumtion compared to before at say 65 mph or a nice cruise speed?
28 bravo1 @ just under 5300 rpm. Going for labbed 30 next season :winker:
Drive still up and running, But I run a Billet marine drive cap with HD bearing and built in water cooling passages.
My intercooler dumps thru the drive cap.
Not worried to much (knock,Knock)
gas milage at cruising rpm's is better, at 65 mph is better,(turnning less RPM's to get 65) but WOT is worse
Any more trade secrets are going to cost ya :laugher: :laugher:
Last year he bought an XR. So far, so good. I would think your combo with the whipple will be far more forgiving on the drive, at least while pulling in and out of gear (no blower surge).
28 Bravo 1 prop. Stock Bravo 1 - 1:50 drive. Not sure about gas economy at cruise. It seemed about the same. It definately sucked (literally) at WOT.
Just as an example that you may be able to relate to CJ, I filled up before the rally until gas was litterally spitting out of the vent. At the end of the run on Saturday I had used a little less than 1/2 tank, so probably about 45 gallons. That was a combination of idleing, cruising and running pretty good.
Last year he bought an XR. So far, so good. I would think your combo with the whipple will be far more forgiving on the drive, at least while pulling in and out of gear (no blower surge).
I'm not worried about in and out of gear, I'm more worried when I call for all 740 hp.
Splinter, I can kinda relate, the last leg of the ralley, my self, Firstborn, Hard drive, and another went to the Beach grill bar. So I didn't burn fuel at the same rate as you. But I don't think thats to bad really.
Thanx for the info guys. I'm liking this Whipple idea more and more!
My new Procharged engine (540 w/ Carb M4 Procharger) is on the stand now and is going in next week. I have many of the same questions you have, so I have been asking alot of the guys in my area about supercharged engines and drives.
I have had many discussions with people running high HP (some as high as 1300 HP on high boost and N.O.S)through Bravo drives; I think it comes down to:
1. Keeping the drive oil cool . This is done with a drive shower, but a drive shower only works when you are moving. I have plumbed my intercooler bypass to dump on the drive. Another trick that Joel Ross (F2 Velocity) told me is to use the Merc Syn Green oil with ProBlend as an additive. It keeps temps down.
2. Shifting in and out of gear under 1000 RPMs. Not a concern for whipple, procharger or vortec. Mainly for roots blowers with surge.
3. Ease into the throttle- slamming it to the dash is something I wouldn't do naturally aspirated or blown.
4. Pull all the way back on the throttles for reentry if airborne.
Numbers 2,3 and 4 are common sense, but keeping the oil cool is the key to longevity in the drive and as well as in the engine for WOT blasts.
Yup #2 3 and 4 I learnt after two drives on my last boat. What is this problend you speak of? I'm using Quiksilver drive lube now. I too will dump water on top of the shower aswell as run the pick up tube from the bottom. The more water the better right!
What is this engine of your going in? not a 25' is it!
Many of us in the Washington DC area use Problend mixed with Quicksilver in our Bravos.
Yes, this motor is going in my 25'. The past 2 seasons I had a 502 that was 10:1 compression. Never dynoed it, but probably just above 500HP conservatively. I ran a best of 81.1 with that. I also have an Imco 2" shorty.
This year with the Procharged 540, I will be making considerable more torque so I changed the lower gears in the drive to a 1:25 gear ratio. I feel that I can still get great acceleration and cruise with that ratio without having to spin a large pitch prop. I found that the larger pitch props torque my Aggressor over since it has a 7' beam.
I will post some pictures of the engine and with the engine in the boat next week.
Thank you very much for your concern. Safety is a top priority when boating. I have a beautiful wife and daughter that I boat with the majority of the time. Ror the most part, this boat will be used for cruising between the speeds of 45 and 60 on the mostly calm Potomac River.
I built the 502 thinking it would be a perfect engine for this size boat. I found that I was running it harder (4000 + RPMs) to achieve a 55 - 60 MPH cruise. I should be able to achieve this at 3000 to 3300 RPMs with the 540/M4. I also feel that the most fun part of having horsepower is acceleration and getting out in front of other boats you are running with.
I have learned to respect speed and/or power and the conditions in where it is responsible to apply it. Just like the Suzuki GSXRs that I have had in the past, you must respect what you are riding/driving.
If there are any WOT passes to be made, they will be done by myself wearing a vest and cut-off switch.
I am going to spend considerable time working on dialing this boat in, not for speed, but for handling as well. Correct prop, x-dimension, trim/tab position and water conditions are much more critical on my boat than on your 288 or larger boats.
I truely appreciate yours, as well as others concern for safety and I just wanted to let you know that I am not one to drop a huge HP engine in a small boat and slam the throttles to the dash. As I mentioned before, this will have to be respected.
good to hear, I'm not worried. It takes experiences, and mistakes /close calls to learn some times. I have all, but you never stop learning till you die.
Your target for that boat Aggressor is the same as me. I'm not supercharging to run WOT all the time. Our group of friends are all between 70 and 80 top speeds. But we all cruise around 55 or 60. Its the every now and again we open up, that I would like to be in front, like anyone. Once that is done, I pull back and let others pass.
As of now, I will hold mine WFO for a long period of time if we are in a fun run or poker run. But once its supercharged, I won't have to. This is what I believe! My name is Jeff.
There, now that we have justified a supercharger, lets get back to main subject.
You mentioned X Factor, are planning on changing it?
X-dimension is something that I found was too low with my 1997 Aggressor. I went from a standard length drive on that boat to an Imco 2" shortened drive. I picked up 4 mph and the boat drove completely different. Better in my opinion, with less need to trim as high.
I now have a 2001 Aggressor that when measured has a higher x-dimension (about 3/4" higher than my '97), but I have the same 2" shortened drive.... I am going to have to do alot of testing to determine if it will be to high now. Only time on the water will tell. Another person with a 7" beam boat has had great results from a Hydromotive 5 blade and shortened drive that is left hand, rotating counter to the engine torque rotation. He told me that it handles very well and stays straighter through acceleration.
The five blades are supposed to help with higher than average x. If I can I may have the tips of my worked 26
Bravo cupped to help before I go with a drive spacer. I have a 1/2" and 1" available to try.
I have been told by many (who have been there/done that) when substansial horsepower is added that it is not beneficial to trim the drive as much as previously driven with less horsepower. It is just wasted energy. The thrust should be parallel to the waterline slighly piercing the top, not trimmed up, leveraging the bow up. As long as you can carry the bow and get up on the pad the power will be applied more efficiently thrusting through the water, not making a roostertail into the air.
Luckily, I will have a lot of different props and drive spacers to try, slip factors to calculate and help from alot of educated friends to help me dial this one in. It should be interesting.
That makes sense. Right now I trim out to around 1 or 2 on the gage for top speed. 5 is level with the hull. I hope I won't have to do a thing. Just drop it off and pick it up a week later, water teted and all, turning 5400 rpm.
Sounds like you have a good shop who can do the job for you and water test it. That is outstanding.
You or who ever is doing your whipple will certainly have to change props, up probably 2-3 inches in pitch. The whipple is a great system. I also have another friend who has a single engine 32 Dominator with a 500efi/ITS box / XR who is going to whipple next year. Keep me posted, I am going to be interested in the results. He sold his 2000 288 with a 454Mag and whipple and bought the single 32. He said he would boat a few seasons with the 500efi, but my bet is he will whipple it this winter instead of next.
For me, I am making so many changes at once that it will be difficult to do an apples to apples comparison...
same type boat, but different year
going from 1.50 drive ratio to 1.25
N/A 502 to Procharged 540
Hot To Go racing has Quoted me. They are out of Buffalo NY. Only six or seven hours away. He installs the kit (he's a Whipple dealer), installs two gages boost and fuel press, re props it, and water test it. Done ready to go. I have talk to one of his customers and they are very pleased with HTG work and service. Oh, he is also a Sunsation dealer. So if there are any questions, he has the access to the answers. Drop the boat over the weekend, come back the next with a faster boat, propped!
WOW, I must be doing something wrong??? One week later and out on a dialed in boat!!! It has taken me since last fall to get to this point.
No, seriously, I have no one to blame but myself. I pulled the 502 from my 97 last fall with all intentions of making it a 540 and reinstalling it. I came across a 2001 Aggressor, so I sold my 97 with a 454 Mag, last spring. The weather was mostly rain in the beginning of the summer and I just bought a new house last month so I did not do much with the boat. Now I am going full steam ahead to get this thing finished, dialed in, and put away for a great season next year.
At least that is the plan.... we will see if I can make it happen.
Good luck! I was looking for some one who has done more than one install on the same engine as mine , and, that wasn't to far away. I think I've found that guy.
I guess I can post the pricing, complete before taxes, $8500 USF. For amother $4500 he would rebuild the drive with new internals that he has yet to have one fail.
I'm going to pass on the drive up grade, rebuild mine over the winter, and probably wait till the spring to supercharge. Just to see how business goes over the winter.
I thought that was a great price!
Wow Jeff,
You are a motivated man about all this. Let me know if you need any help (besides financial... you're on your own there bud!) with this project.
I agree that $8,500 is a pretty darn good price. The kit alone is $7,200 the prop will run about $600, gauges will be at least $100 and don't forget the fuel pump and fitting he will need to separately purchase for this kit that will most likely cost $600 - $700 for the whole sha-bang. So he's either charging you nothing for the labor, or getting one hell of a deal on the SC kit. I would recommend getting a "build sheet" from Rob at HTG detailing every little part that is included in the quoted price. I would hate to hear you get nickle and dimed to death for misc. items not included. My nickle and dimes added up to about $2000 over a year of dialing things in. Also, make sure you specify a prop. I remember talking to Rob about Spinelli, and him claiming decent numbers with his props. I'm pretty sure both you and I share a totally different view!
As far as the trimming debate goes, I think a lot of parameters make a HUGE difference in the amount of trim needed in a boat. Granted, most of my experience has been with a twin engine Sunsation... I think a majority of it still applies. I noticed that simply the pitch of a prop alone has a lot to do with the boats ability to carry the bow. When I had my stock 32' Bravo - I's labbed, a little bit of pitch was removed to increase the engine RPM's. Albeit very subtle, I did notice less bow lift from the props. Also, the surface area of the old Spinelli's is much less than the Bravo's (which is why the totally suck getting on plane), but the Spinelli's had significantly more bow lift. However, the Bravo's were about 3 - 4 mph faster on top end.
Other considerations are hooks in the hull. I don't believe the 288 has any significant hooks, but the 32's definitely has a hook running along each strake at the transom. I've also heard of the 24 / 25 Sunsation's have a pretty good sized on the back somewhere. I've talked with Joe and Wayne about these hooks at the last Rally. They told me these hooks were specifically engineered into the boats. They also told me these boat's weren't engineered to go 90 - 100 mph. I was told that I would be "on my own" once I start farting around with the hull design (which is what I would expect any manufacturer to say).
Ty, keep us all updated on your project!
-Bayley
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